Impacts on existing restorations

Dental restorations are subject to unacceptable discoloration even when using home systems. [14] Ceramic Crowns – Aggressive whitening can chemically react with ceramic crowns and reduce their stability.[14] Amalgam dentistry – Exposure to carbamide peroxide solutions increased mercury release for one to two days.[44][45] The release of amalgam components is said to be due to redox activity. This increase in the release of amalgam mercury is proportional to the concentration of carbamide peroxide. [46] Resin Composite – Strengthens the bond between enamel and weakens resin-based fillings.[47] Several studies have found that 10-16% carbamide peroxide tooth whitening gels (containing approximately 3.6-5.76% hydrogen peroxide) lead to an increase in the surface roughness and porosity of the composite resins. [46] However, saliva may have a protective effect. In addition, changes in the reflectance of the compound after bleaching with a high concentration (30-35%) hydrogen peroxide were analyzed. [46] This indicates that tooth whitening adversely affects the restoration of composite resin. Glass ionomers and other cements – Studies indicate that the solubility of these materials may increase.[48][46]